1. Field of the Invention
The present invention relates to an information recording method, an information recording device, etc. wherein information is recorded to a multilayer recording medium wherein a number of record layers are laminated and recording of information to each record layer is possible.
2. Description of the Related Art
Japanese Laid-Open Patent Application No. 2001-126255 discloses an information recording device in which recording of information to a write-once recording medium of two-layer structure is performed first from a back-side record layer of the two layers.
Japanese Laid-Open Patent Application No. 11-031357 discloses the technology of information recording in which a single file is divided into data blocks, and division recording of the data blocks is carried out in which the data blocks are individually recorded to a plurality of record layers, in order to prevent the duplication of the file data.
It is known that, in a DVD-ROM disk, the two or more record layers are laminated, and the data is recorded to each record layer. That is, it is specified that the optical disk (DVD5) has only the first layer, and the optical disk (DVD9) has the second layer as well. Moreover, the double-sided versions (DVD10, DVD18) of these optical disks are also known.
The DVD9 is not an optical disk which is completely different with the DVD5, but it is almost the same, and few problems arise with the reproduction of the data of DVD9.
Although the storage capacity of DVD9 is not equal to twice that of DVD5, this is because the recording density is lowered and the interaction with each record layer is inhibited.
Thus, the storage capacity of the optical disk with two or more record layers does not necessarily become the integral multiple of the recording amount of the optical disk only with the single record layer. Similarly, the recording method is also affected, and it cannot necessarily be performed in the same manner.
On the other hand, as rewritable DVD media, the DVD one side of which is provided with two or more record layers and the compatibility is taken into consideration, and the blue-ray disk (called “two-layer DVDR”) are likely to be realized.
The storage capacity of the two-layer DVDR is 8.4 Gbytes which is about twice the storage capacity of the conventional one-layer DVD+R, which is 4.7 Gbytes. The recorded data can be read from the two-layer DVDR with the DVD player which is capable of reproducing the read-only DVD disk with the two layers of one side, or with the DVD-ROM drive.
When recording data to the two-layer DVDR, for a data area where data is recorded in one of the two record layers, data must be recorded also on the corresponding data area of the second layer. If there is the difference in the size of the data area of each record layer, the difference region needs to be recorded by dummy data or lead-out. This is to take the compatibility on the logic format with the read-only two-layer DVD.
Moreover, for example, when the user reproduces the data of the first layer, there is the case in which the data is not recorded on the second layer of the same radius position of the disk and the read head is placed to the second layer by chance during the seeking to the target address and the laser focusing is met there. In this case, the problem arises in that the data of the first layer cannot be reproduced with the read head. To avoid the problem, it is necessary that, when data is recorded in a data area of one of the two record layers, data be recorded also on the corresponding data area of the second layer.
Therefore, when the user data recording is completed without hardly recording the user data in the second layer at all or when the user data recording is completed with the second layer un-recorded, another problem will occur in that the processing to fill all the corresponding non-recorded data area of the second layer with the predetermined data must be performed before starting the data recording. It takes a long time to carry out the processing to fill them with the predetermined data.
Moreover, the logical address (LBA) in the two-layer DVDR is continuously assigned from the starting address of the data area of the first layer, and the logical address continues from the data area ending address of the first layer to the data area starting address of the second layer.
That is, when the user performs data recording continuously, it is started from the data area starting address of the first layer and completed at the data area ending address of the first layer, and it is performed in succession from the data area starting address of the second layer. Thus, the user is allowed to record the user data in the two-layer DVDR without being conscious of the two record layers.
For this reason, there is a conceivable case in which the user data recording is finished without completely recording the user data in all the data area of the second layer or with some of the data area of the second layer unrecorded. The above problem remains un-resolved.
In the case where the data recording is finished in the middle of the data area of the second layer, namely, the case where the user data recording is completed in the state where the non-recorded region exists in the data area of the second layer, the compatibility with the existing reproducing device is not retained. If the non-recorded region exists in the data area of the second layer the disk layout becomes different from that of the read-only two-layer DVD disk.
Moreover, in such a case, when the user reproduces the data of the first layer of the disk, the seeking to the target address may result in placement of the read head to the second layer and the focusing of laser light may be met there. There is the possibility that an error occurs due to impossibility of acquisition of the address information if the data is not recorded at the same radius position of the second layer. As a result, the problem may arise in that the data of the first layer cannot be reproduced.
The same problem arises also when the user data recording is finished without completely recording the second layer at all.
In order to prevent the above problem, the information recording device of Japanese Laid-Open Patent Application No. 2001-126255 functions to divide the recording data into two data blocks, and recording of the data blocks is performed to the two record layers, respectively. When this method is used, the above problem is avoided only in the case where the user data recording to the optical disk is intensively performed once. However, with this method, the additional data recording to the same medium is impossible.
Moreover, in the technology of Japanese Laid-Open Patent Application No. 11-031357, the prevention of the duplication of the file is the sole purpose, and the additional data recording is not taken into consideration.